NCTS (South)


DATE2010-03-11

TIME14:10

PLACER203, 2F, NCTS, NCKU

FIELDLow-Dimensional Systems and Nanostructures

SPEAKER Prof. Shaoyan Chu(儲少岩) - Center for Materials Science and Engineering Massachusetts Institute of Technology

TITLECrystal Growth and Characterization of Spin Frustrated Kagomé Antiferromagnets: Cu4-xMx(OH)6Cl2 (M = Zn, Mg, Cd, Cu, Ni)properties

ABSTRACTDue to the triangular arrangement of ions in a 2D Kagome structure, it is impossible to minimize all nearest-neighbor energies simultaneously. This ‘geometric frustration’ suppresses classical magnetic long-range order (LRO) and is thought to result in novel quantum ground states. The atacamite family, which consists of six members and has a general formula of Cu4-xZnx(OH)6Cl2, is one of the best candidates for studying this new physics. Among them, the basic properties of clinoatamite, paratacamite and herbertsmithite is reviewed and compared with theoretical predications in this work. To settle a dispute on whether the current observed behaviors are the intrinsic properties of materials, a hydrothermal technique has been used in successful growth of millimeter-size single crystals. This technique also produced a series of novel isostructural crystals through substituting Mg2+, Cd2+, Cu2+ and Ni2+ ions for Zn2+. Characterization of these crystals and a comparison of their magnetism are presented.